The MSVC2013 Professional Version installes the amd64 folder with its linker. After changing the compiler of the Qt Kit to:
Microsoft Visual C++ Compiler 12.0 (amd64)
I was able to link the project.

Nethertheless MSVC2013 is now moaning that it needs a developer license, BUT this another topic because MSVC is trying to sign the app at this point. I've created half a year ago a tutorial for myself to pack, sign, certificate, deploy and install an app manually via console commands.